Reference electrode and ion concentration measurement device

Abstract

This invention prevents leakage of an internal liquid and breakage of a reference electrode resulting from volume expansion of the internal liquid due to the congelation of the internal liquid, and comprises a vessel that forms a sealed space, an internal liquid that is contained in the vessel, an internal electrode that is immersed in the internal liquid, an ion conduction part that is arranged on a wall of the vessel and that electrically connects the internal liquid and a measurement sample, and a volume expansion absorption mechanism 6 at least a part of which is immersed in the internal liquid and that absorbs volume expansion of the internal liquid due to congelation of the internal liquid.

The invention claim is: 
     
       1. A reference electrode comprising:
 a vessel that forms a sealed space, 
 an internal liquid that is contained in the vessel, 
 an internal electrode that is immersed in the internal liquid, 
 an ion conduction part that is arranged on a wall of the vessel and that electrically connects the internal liquid and a measurement sample, and 
 a volume expansion absorption mechanism at least a part of which is immersed in the internal liquid and that absorbs volume expansion of the internal liquid due to congelation of the internal liquid, 
 wherein the internal liquid contacts the exterior surface of the volume expansion absorption mechanism, and 
 wherein the volume expansion absorption mechanism comprises an elastic transform part that makes an elastic transformation in accordance with the volume expansion of the internal liquid and a gaseous closed layer that is arranged to make contact with the elastic transform part. 
 
     
     
       2. The reference electrode described in  claim 1 , wherein
 the volume expansion absorption mechanism is a hollow body inside of which a gas is filled, 
 the elastic transform part is formed as a part of a wall of the hollow body, and 
 the gaseous closed layer is provided in a hollow part of the hollow body. 
 
     
     
       3. The reference electrode described in  claim 2 , wherein
 the hollow body is a bag-shaped elastic body inside of which a gas is filled. 
 
     
     
       4. The reference electrode described in  claim 3 , wherein
 the bag-shaped elastic body is an elastic tube that both ends are blocked, and the elastic tube that is arranged from one end part of the sealed space in the vessel to the other end part thereof. 
 
     
     
       5. An ion concentration measurement device using the reference electrode described in  claim 1 .